Make NGFooLayoutAlgorithmTest to use ScopedLayoutNGFragmentCachingForTest

NGColumnLayoutAlgorithmTest and NGBlockLayoutAlgorithmTest have been using
RuntimeEnabledFeatures::SetLayoutNGFragmentCachingEnabled for testing. This cl
removes the use of RuntimeEnabledFeatures, instead make them to use
ScopedLayoutNGPaintFragmentsForTest.

Bug: 769541
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Change-Id: I4794372fedbe4df6bdc0167487b95b4295970e2a
Reviewed-on: https://chromium-review.googlesource.com/758308
Commit-Queue: Gyuyoung Kim <gyuyoung.kim@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515124}

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm_test.cc

@@ -18,7 +18,7 @@
 #include "core/layout/ng/ng_physical_box_fragment.h"
 #include "core/layout/ng/ng_physical_fragment.h"
 #include "core/style/ComputedStyle.h"
-#include "platform/runtime_enabled_features.h"
+#include "platform/testing/RuntimeEnabledFeaturesTestHelpers.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace blink {
@@ -30,9 +30,6 @@ using ::testing::Pointee;
 class NGBlockLayoutAlgorithmTest : public NGBaseLayoutAlgorithmTest {
  protected:
   void SetUp() override {
-    // Make sure to reset this, except for the one test that needs it.
-    RuntimeEnabledFeatures::SetLayoutNGFragmentCachingEnabled(false);
-
     NGBaseLayoutAlgorithmTest::SetUp();
     style_ = ComputedStyle::Create();
   }
@@ -89,7 +86,7 @@ TEST_F(NGBlockLayoutAlgorithmTest, FixedSize) {
 }
 
 TEST_F(NGBlockLayoutAlgorithmTest, Caching) {
-  RuntimeEnabledFeatures::SetLayoutNGFragmentCachingEnabled(true);
+  ScopedLayoutNGFragmentCachingForTest layout_ng_fragment_caching(true);
 
   SetBodyInnerHTML(R"HTML(
     <div id="box" style="width:30px; height:40px"></div>

third_party/WebKit/Source/core/layout/ng/ng_column_layout_algorithm_test.cc

@@ -14,9 +14,6 @@ namespace {
 class NGColumnLayoutAlgorithmTest : public NGBaseLayoutAlgorithmTest {
  protected:
   void SetUp() override {
-    // Make sure to reset this, except for the one test that needs it.
-    RuntimeEnabledFeatures::SetLayoutNGFragmentCachingEnabled(false);
-
     NGBaseLayoutAlgorithmTest::SetUp();
     style_ = ComputedStyle::Create();
   }